Because they don't have the meta-cognition for this. — schopenhauer1
How do you know that they don't have the meta-cognition for this? If as you have said this is true, there must be some evidence of it.
To know one's own likes and dislikes (and not just "dislike" in the moment as a primary perception) is to have a model of self, which as far as we know really requires language.
Our species happened to evolve in the unique trait of linguistic mental capacities which then ratcheted the brain in a co-evolution of sorts to have abilities that co-opted this capacity with more plasticity, episodic memory, and learning (which allowed for more cultural input rather than hard-wired or rudimentary learning techniques). — schopenhauer1
Again, what proof do you have that language is necessary to have a model of self. We don't even know if animals have language or not. There are many theories but no real evidence in either direction. How can you be sure that there are not animals that have a language hard wired into them. There is an theory about this question but I will let you find it.
The language centers and co-opted centers that evolved with/from this were taken from more primitive centers I agree (i.e. mirror neurons, FOXP2 gene, the neocortex development, the brocas and wernikes region, etc.). — schopenhauer1
So the only way to develop language is the human way, no other possibilities? We certainly don't fully understand how humans have developed into what we are today, and unfortunately we have even less understanding of how animals have done so. Yes they can to a certain accuracy explain the ancestry of a lot of animal, where the came from, but they still have a long way to go explaining anything other than the obvious physical changes. Little has been done to study animal culture, the norms, customs, rules and so on of the group interactions. And most social animals do seem to have them.
Let me leave you with a joke.
An old monkey was sitting in a tree deep in the African jungle with his grandson. The little one sees some people coming up the hill towards them.
He jumps up and down with excitement and says "Grandad look, people"
The older monkey says "Sit down and shut up"
A few minutes later the youngster says "Grandad look they are almost here"
The older monkey says "Sit down and shut up"
A few minutes later the youngster says "Grandad they are almost here. Lets go down and talk to them"
The older monkey says "Sit down and shut up"
The youngster, almost crying says " But Gramps I want to talk to the people"
The older monkey says "Sit down and shut up"
As the people pass by the young monkey weeps at the lost opportunity. After a while he says " Why did you not want to talk to the people Grandad?"
The old monkey looks at the little one and says " If those white things ever found out we could talk they would drag us away and make us work for nothing like they did with those black things that used to live down by the river."